RecursionBane has asked for the
wisdom of the Perl Monks concerning the following question:

Greetings, Monks!
I would like your opinion on any weaknesses in this (sufficiently random) random string generator in order to build universally unique identifiers (UUIDs). These UUIDs are used only on the local network to identify frequent build processes, where each build should be individually addressable.
I understand that there are several CPAN modules claiming to provide near-random numbers and even UUIDs, but I'm looking for an alphanumeric string, so I went with a simple, custom approach.

Update: I didn't have time to elaborate earlier. But the point here is that seeding correctly is hard. Generating strong pseudo-randomness is hard. But this is a problem that has been solved already (on CPAN), with a good deal of research, and collaboration. And to get well seeded, high quality random bytes, you need one module, which has exactly three non-core dependencies in its heritage, if you exclude what Test::Warn drags along with it. ...and it works portably across many platforms, and back through Perl 5.8. In some cases even 5.6.

As others have mentioned there are flaws in the seeding you're using. And an MD5 RNG is less than ideal.

if you need a readable UUID simply use Data::UUID like this my $uuid = Data::UUID->new()->create_str();. This will create a UUID that looks like 4162F712-1DD2-11B2-B17E-C09EFE1DC403. This is an alphanumeric string.